Non-pacemaker cells are what type of response?

Non-pacemaker cells are what type of response?

• A. Slow-response
• B. Fast-response
• C. Plateau-type
• D. Transient-response

Answer: (B)

Non-pacemaker cardiac cells, such as atrial and ventricular myocytes and Purkinje fibers, generate a fast-action-potential upstroke. This rapid depolarization is driven by the quick opening of voltage-gated Na+ channels, giving a steep phase 0 and high conduction velocity through the heart muscle. The resting membrane potential stays relatively stable, and after the fast upstroke, Ca2+ influx through L-type channels creates the characteristic plateau (phase 2) that supports contraction before repolarization. Pacemaker cells, by contrast, rely on a slower Ca2+-mediated upstroke and automatic phase-4 depolarization, which is why they’re described as slow-response. So non-pacemaker cells are fast-response.

Non-pacemaker cardiac cells, such as atrial and ventricular myocytes and Purkinje fibers, generate a fast-action-potential upstroke. This rapid depolarization is driven by the quick opening of voltage-gated Na+ channels, giving a steep phase 0 and high conduction velocity through the heart muscle. The resting membrane potential stays relatively stable, and after the fast upstroke, Ca2+ influx through L-type channels creates the characteristic plateau (phase 2) that supports contraction before repolarization. Pacemaker cells, by contrast, rely on a slower Ca2+-mediated upstroke and automatic phase-4 depolarization, which is why they’re described as slow-response. So non-pacemaker cells are fast-response.